The SG Arrival Card combines your entry declaration and a health/customs declaration into a single online form, replacing the old paper disembarkation card. Every visitor completes it, regardless of visa status.
What it covers
Passport details, flight/travel information, accommodation address in Singapore, and a short health declaration. It takes a few minutes to complete online.
When to file it
Within three days before you land. Filing it a day or two ahead — rather than at the gate — avoids any risk of a brief site outage during boarding.
If you forget
Kiosks are available at Changi Airport immigration for anyone who lands without having filed it, though this adds time at the checkpoint — worth avoiding if you can.